Modern printers use a variety of inks to generate images from data. These inks may include liquid ink, dry ink, also know as toner, and solid ink. Both solid ink and ink jet printers utilize a print head that ejects liquid ink onto media, for example paper. The print head in a liquid ink printer typically oscillates back and forth on a transversely moving carriage that is placed over longitudinally advancing media. So-called “solid ink” refers to ink that is loaded into a printer as a solid, which is typically in stick or pellet form. The solid ink is melted within the printer to produce liquid ink that is supplied to a print head for ejection onto media or an intermediate member to generate a printed image from image data. The intermediate member may be a drum onto which the ink is applied as the drum rotates and the print head moves across the drum. These solid ink printers typically provide more vibrant color images than toner or ink jet printers.
The print heads for liquid ink and solid ink printers typically include a plurality of ink jet nozzles that are arranged in a matrix within the print head. The ink is ejected from the nozzle by applying a pressure pulse to the fluid ink in a supply tube. In other print heads, the pressure pulse is generated by a micro actuator. Each ink jet nozzle in a print head has a micro actuator for ejecting ink from the print head. In a thermal ink jet print head, the actuator is a heater while in a piezoelectric ink jet print head, the actuator is piezoelectric material. In other print heads, the pressure pulse may be generated by a micro mechanical membrane.
An ink ejecting print head typically includes an internal manifold that is in fluid communication with the ink jet nozzles through a large number of closely spaced apart ink channels. The ink channels may be formed by, for example, laminating a stack of metal plates. The small dimensions of these channels and the need for tight tolerances to provide uniform nozzle performance in a print head make print head manufacture challenging.